XVII INSECTA: COLEOPTERA 265 



water- weed. Feed on "gentles." In the spring, be on the look-out 

 for egg-laying, and if this is detected, remove the eggs, with the 

 water-plant in which they are inserted, to a smaller tank and 

 watch their development. If eggs cannot be obtained, larvae 

 should be caught from the ponds and their development watched. 

 Great care must be taken to give the full-grown larva a suitable 

 earth bank rising above the water, in which it can pupate. 



2. Keep the Silver Water Beetle in the same way. This beetle 

 feeds almost entirely on water-weeds, and can be kept, therefore, 

 in a tank with other creatures, though in the spring it is well to 

 keep one tank for these beetles alone, so that the formation of 

 the egg-cocoon in May may be seen. 



3. Collect from the ponds any other water beetles or beetle 

 larvae obtainable. Keep them carefully apart, and identify them 

 speedily, so that their ways may be. ascertained and suitable food 

 given them. Their life-histories may then be worked out. 



4. Search any plant which is infested with Green-fly for Lady- 

 bird eggs, larvae, pupae, or full-grown beetles. Isolate one larva on 

 a twig covered with Green-fly, and determine at what rate the 

 larva devours them. Work out the life-history in detail, making 

 careful illustrations of each stage. 



5. Study any other live Land Beetles that are available, keeping 

 careful records of your observations, even when incomplete. It 

 may be possible to complete them at a later date. 



